1. Field of the Invention
The present invention relates to a method of patterning a conductive polymer layer, an organic light emitting device (OLED), and a method of manufacturing the OLED, and more particularly, to a method of patterning a conductive polymer using a charged particle beam, an OLED manufactured by the method of patterning the conductive polymer using a charged particle beam, and a method of manufacturing the OLED.
2. Description of the Related Art
OLEDs have received much attention due to their suitability for color display devices. OLEDs are emissive display devices that emit light using an organic compound. They are thin, and compared to TFT-LCDs, have lower manufacturing costs, lower power consumption, and quicker response time, due to their simple structure and manufacturing process.
OLEDs are devices that transform electrical energy into optical energy in an organic material, to emit light by generating excitons by recombining holes and electrons respectively injected into an anode and a cathode of the organic material.
The OLED includes a metallic cathode, an emission material layer (EML, or a light emitting layer), and an anode, which are sequentially stacked on a basic stacking structure. The performance of the OLED is largely affected by the variation of a multi-layer thin film structure, and the light emitting efficiency and lifespan of the OLED can be improved by adding various functional layers, such as a hole transfer layer (HTL) and an electron transfer layer (ETL), to the basic structure.
The hole transfer layer (HTL) includes a hole injection layer (HIL), a hole transport layer (HTL), and/or a electron blocking layer (EBL). The hole transfer layer (HTL) may be formed of electron donor molecules having low ionization potential to facilitate the hole injection into the hole transfer layer (HTL) from the anode. If the hole transfer layer (HTL) is formed of triphenyldiamine (TPD) monomer and the TPD monomer is exposed to heat for many hours, the TPD monomer crystallizes and loses its hole transferring characteristics, since the TPD monomer has low thermal stability. Therefore, conductive polymers having high thermal stability and conductivity, such as polyethylenedioxythiophene (PEDOT) or polyaniline (PANI), are used for forming the hole transferring material. Also, to use the OLED as a display device, a method of patterning a conductive polymer layer through a photo process after spin-coating the conductive polymer layer on a substrate has been considered.
FIG. 1 is a perspective view illustrating a conventional method of patterning a conductive polymer for an OLED (refer to Korean Patent No. 2003-044562).
Referring to FIG. 1, the conventional patterning method includes forming a PEDOT layer 120 on a glass substrate 110 by spin-coating, and forming an insulating layer 150 and a hole transport layer (HTL) 140 by radiating high-energy UV rays or X-rays through a photomask 130 onto the glass substrate 110 on which a PEDOT layer 120 is coated.
The conventional method of patterning a conductive polymer forms a conductive polymer pattern using the photomask 130 by radiating high-energy photons, such as UV rays or X-rays.
The conventional method of patterning a conductive polymer uses photons, which have the characteristics of refracting, reflecting, and interfering. It is difficult to control the photons passing through the photomask 130, and an imperfect pattern may be formed due to wave guiding of the photons. When the gap between the photomask 130 and the PEDOT layer 120 is reduced to reduce the wave guiding of the photons, the PEDOT layer 120 can be contaminated by contacting the photomask 130. Furthermore, the conventional method of using high-energy photons to pattern a conductive polymer has a high power consumption.